When I was growing up, my parents insisted that we not talk about our vacation plans in public, lest someone overhear and break into our house while we were gone.

These days, kids and even many adults think nothing of telling the world - or at least their 795 closest friends - that they're not at home by posting their whereabouts or vacation plans on Twitter, Facebook or other social media.

Israel Hyman, an Arizona video editor who says he has close to 2,000 people following him on Twitter and also uses Facebook "a lot," recently was burglarized while he was in Kansas City.

"We had mentioned that we were going out of town for an extended period and even Twittered about the trip as we drove for three days," he told an Arizona television station. While he was gone, video-editing equipment was stolen from his home. Although he is not sure his tweeting tipped off the burglars, he says he will be more careful in the future about what he shares online.

"People just don't realize the kind of information they give out in social-networking sites can be used on its own or with other information to commit identity theft and other fraudulent activity," says Paul Stephens, director of policy and advocacy with the Privacy Rights Clearinghouse.

Most social-networking operations let users restrict access to people they approve. But many people fail to take this important step, especially if they are seeking a wide audience or trying to look ultra-popular.

Others assume they are safe because they restrict access to the kind of friends they would share their vacation plans with in person. What they forget is that these friends may share that information. "There is nothing to stop them from showing it to someone else or doing a screen capture and sending it on to somebody," Stephens says.

According to the British government Web site Get Safe Online, 13 percent of social-network users report posting friends' pictures without their consent and 7 percent report posting friends' contact information without consent. Those most likely to give away their friends' information are 18- to 24-year-olds.

Know your friends

If your kids tell you they are networking only with "friends," beware. "What an adult thinks of as a friend and what a friend is in social media are two different things," says Peter Spicer, communications manager with Chubb Personal Insurance.

Spicer says parents should remind their kids "not to post the fact that we are going on vacation. That's a heads-up to criminals." Tell them it's OK to post pictures and talk about the trip after they're home.

Joanne McNabb, chief of the California Office of Privacy Protection, says she hasn't received any complaints from people who think they were robbed because they disclosed their whereabouts on social networks. But, she says, "It's a risk in the online world just like in the offline world."

Robbers have long been known to scour the newspaper for death or wedding announcements and target homes when families are likely to be at the funeral or on a honeymoon.

"It's not that these Web 2.0 things are creating new crimes. They are providing some new vectors or venues for the crimes that can happen anyway," McNabb says.

While you're away

Stephens says vacationers also need to protect themselves against identity fraud when they're away from home.

-- Photocopy or make a list of the contents of your wallet. Keep it in a locked location at your hotel or with a trusted person at home whom you can contact if your wallet is lost or stolen.

-- Don't carry unnecessary credit cards, your Social Security card or other documents that could compromise your identity if lost or stolen. If you have a Medicare card, make a photocopy without the last four digits of your Social Security number.

-- Carry two credit cards. If you carry only one and it is deactivated because of suspected fraud or the magnetic strip gets damaged, you'll be in trouble until it is replaced.

-- Use traveler's checks or credit cards. Leave your checkbook in a secure locked place at home. Do not use debit cards (check cards). This reduces your vulnerability to having your checking account emptied while you are on vacation.

-- When dining in a restaurant, try to keep an eye on your credit card. If the server removes your card from sight, he may be able to create a "clone" by using a portable card skimmer that will copy the information from the card's magnetic strip.

-- If you are bringing your laptop, be careful when using it to access online banking or other password-protected services from Wi-Fi networks. Be sure to use Wi-Fi hotspots that are secure. For Wi-Fi tips, see links.sfgate.com/ZHHR.

-- Don't access sensitive information from a cybercafe or other public computer because keyloggers (software that can track your keystrokes) may be tracking you.